(22b) Multi-Scale Modeling of Particle Flows in Granulators

Several researchers have attempted to couple discrete element method (DEM) and population balance (PB) models to predict granulation process performance. These studies have attempted to combine the strengths of DEM for modeling particle-scale phenomena such as collision frequency and collision velocity distributions, with the strengths of PB models for modeling macro-scale granulation processes over longer time scales. Here we present a different approach to combining DEM and PB models. Particle trajectories taken from the DEM model are used to generate an intermediate compartment model of particle flow through the spray zone of a paddle granulator, which can then in turn be easily used within a PB model framework. The compartment model presents a simplified, but still accurate, description of the particle residence and circulation times in the spray zone. The development of the DEM model and corresponding compartment model will be presented.